terraformingfandomcom-20200214-history
Atmosphere Cooling Effect
Atmosphere cooling effect will occur when temperatures beyond the protective layers of Greenhouse Gases fall below freezing point of gasses in the atmosphere. This causes the celestial body to cool down. Principle Every gas has a critical temperature known as freezing point. Below that temperature, it will freeze. A certain amount will still sublimate and be in gaseous form. With the use of greenhouse gasses, it is possible to increase surface temperature of a terraformed planet or moon up to a value compatible with human life (15 degrees C), even if otherwise temperature will fall to -200 degrees C or even below. However, greenhouse gasses are heavy and they will tend to accumulate at lower altitudes. Above them, there will be a cooler atmosphere. Above the greenhouse insulation, temperature will fall to values found prior to terraforming. Oxygen and nitrogen will freeze, forming clouds and hazes that will slowly fall down towards the lower atmosphere. Condensation will occur faster if the planet is further away from its sun. Hazes will fall faster if the gravity is higher. As frozen gasses fall to the lower atmosphere, they will heat and rise back in the upper atmosphere. As this happens, temperature in the lower layers will fall significantly. Effects Nearly any Outer Planet will have a type of climate named Monoclime, with very little temperature variations between seasons, between latitudes and between day-night cycles. Because of this, moisture will accumulate in the atmosphere up to 100%. Multiple layers of clouds and hazes will form, but since temperature will remain constant, it will not rain significantly. The sky will be almost permanently covered with clouds. Such a wet environment is not friendly to human life. Atmosphere cooling events will not occur continuously. They will occur in waves and not on the entire surface at once. During a cooling event, temperature will drop, forcing the atmosphere to lose moisture. It will rain and the rain will mostly come from the upper layers of the atmosphere. Ground temperature will drop as cold air will reach the surface. But, since the air will lose most of its humidity, the sky will become blue. Light will reach the ground and slowly temperatures will start to rise. Temperatures Oxygen melting point is -218.8 C and boiling point is -183 C. Nitrogen melting point is -210 C and boiling point is -195.8 C. These values are for a pressure of 1 bar. It is important to note that both gasses have similar freezing and boiling temperatures. At the orbit of Uranus, average day temperature above greenhouse layers will be -170 C, but during night, they will fall to -200 and below. Also, the moons of Uranus have a highly tilted axis, allowing long polar nights to happen. At the orbit of Neptune, temperatures are around -200 C, low enough to enable atmosphere cooling events to happen. At the orbit of Pluto and beyond, it is even cooler. At the orbit of Uranus, atmosphere cooling events will be rare and mostly during polar nights. However, at the orbit of Neptune, they will be far more common. There is a critical point, beyond which, terraforming seems impossible without an extra source of heat. The inner atmosphere is heated by the dim light from the Sun (or another star, for extrasolar planet). The further the planet, the less heat it will receive and the more often atmosphere cooling effects will be. Beyond a certain limit, the lower atmosphere will not be able to absorb enough heat to counter atmosphere cooling effects. Temperature will fall below water freezing point, making human life difficult. Because of this, for a far outer planet, even if temperature could in theory be kept to 15 C (see Greenhouse Calculator for details), in practice, it might not be possible. Because of this, distant worlds like Eris might be unable to support an average temperature of +15 C. Even so, Earth - like plants cannot survive below a Solar Constant of 0.002, which is found at the orbit of Neptune. Category:Habitable Factors